Avast! - Stop and give attention. It can be used in a sense of surprise, "Whoa! Get a load of that!" which today makes it more of a "Check it out" or "No way!" or "Get off!"

Aye! - "Why yes, I agree most heartily with everything you just said or did."

Aye aye! - "I'll get right on that sir, as soon as my break is over."

Arrr! - This one is often confused with arrrgh, which is of course the sound you make when you sit on a belaying pin. "Arrr!" can mean, variously, "yes," "I agree," "I'm happy," "I'm enjoying this beer," "My team is going to win it all," "I saw that television show, it sucked!" and "That was a clever remark you or I just made." And those are just a few of the myriad possibilities of Arrr!